PLEASE HELP! BIG POINTS!!!!;)

Answer:
2.5
Step-by-step explanation:
ok so triangle RST is half the size of triangle XYZ
cuz RT equals 8 and XY equals 16 meaning their half the size (8 x 2 = 16)
so all we have to do is divide 5 by half : 5/2 = 2.5
~batmans wife dun dun dun.....